We studied the bioconversion of untreated/ pretreated lignocellulosic biomass by fungus Myceliophthora thermophila SH1 under solid state fermentation. Pretreated lignocellulosic biomass has emerged as a suitable substrate for cellulase and xylanase production by M. thermophila SH1 reaching upto 35.32 U/g cellulase and 203.20U/g of xylanase in NaOH+H2O2 pretreated Populus deltoides wood. Comparative study of bioethanol production from P. deltoides wood was carried out using different methods of non-detoxification/ detoxification, enzymatic hydrolysis and fermentation. In method I and II supernatant of alkaline hydrogen peroxide pretreated P. deltoides wood was pooled together with enzyme saccharified residue fraction, while in method III and IV supernatant after pretreatment was discarded and only enzymatic hydrolysate containing simple sugars was used for the fermentation. Different ethanologenic yeasts and bacteria were employed under monoculture and co-culture combinations for fermentation. The highest ethanol yield of 13.40 g/l was obtained in method IV by monoculture of S. cerevisiae II.